The 2 millimeter band is a portion of the EHF

EHF

EHF may stand for:* EHF – therapy * Extremely High Frequency, a radio frequency band* Ebola hemorrhagic fever, an illness* European Handball Federation, the European governing body for handball...

 (microwave

Microwave

Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

) radio spectrum internationally allocated to amateur radio

Amateur radio

Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...

 and amateur satellite use. The amateur radio and amateur satellite band is between 134 GHz and 141 GHz. Amateurs operate on a primary basis between 134 GHz and 136 GHz and on a secondary basis in the rest of the band. Also, amateurs must protect the radio astronomy

Radio astronomy

Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...

 service
from harmful interference between 136 GHz and 141 GHz. The ITU's allocations are the same in all three ITU region

ITU region

The International Telecommunication Union , in its International Radio Regulations, divides the world into three ITU regions for the purposes of managing the global radio spectrum...

s.